Currently 12 businesses have been approved by the industry regulator Therapeutic Goods Administration (TGA) to grow or manufacture medical marijuana in Australia, ABC reports.

Medical marijuana farmers have to spend up to half a million dollars on security who must protect their crops from thieves wanting to put it on the black market (stock picture)

Operators are required to first prove their crop is not able to fall into the wrong hands, and must secure their crops costing upwards of hundreds of thousands of dollars, according to Adam Benjamin from Medifarm, Sunshine Coast-based growers.

'Depending on the size of your facility it moves into the hundreds of thousands of dollars, so you need money in the bank,' Mr Benjamin said.